Where did Rudolf Diesel get his inspiration?

After doing a little research on Rudolf Diesel and how he came up with the diesel engine I came upon this information. From looking at pictures of early refrigerators and early diesel engines it is clear they look about the same.  They both stand on two legs and have a single piston in the middle. They look like little Eiffel Towers.

It is easy to see Rudolf was influenced by his teacher Carl Von Linde. Together the teacher and student worked on refrigeration . The principles of heat and how it behaves  helped the two understand and manipulate energy  .

So it doesn't really matter whether you are trying to keep food cold or produce mechanical work. If you know how energy behaves you can do many things.

Another possible influence was the Fire Piston. These little devices use compression ignition to heat tinder past its combustion temperature. Apparently Carl Von Linde gave a  talk about thermodynamics in the Philippines back in the mid 19th century. He was surprised to see the people there lighting fires with these ancient devices whose origin goes back before recorded time.

When Carl Von Linde got back to Europe he lit a cigarette with a fire piston and Rudolf was impressed. I am not sure if this is true but it is an interesting story anyway. Plus fire pistons had been around Europe for awhile although the match made them less popular.